Abstract

We pioneered and demonstrated the attoclock which is a powerful, new, and unconventional experimental tool to study fundamental attosecond dynamics on an atomic scale. We have demonstrated the first attoclock [1] with the goal to measure the tunneling delay time in laser-induced ionization of helium and argon atoms [2] and to clock the release of the two electrons in double ionization of argon [3] – everytime with surprising results. Theory has failed to offer definitive answers.Time-dependent Schrödinger equation (TDSE) simulations have failed due to numerical problems and simpler semi-classical models are required to capture the essential physics. These semi-classical pictures in strong laser field interactions have been responsible for the rapid progress in this field. A precise measurement of the electron emission angle reveals that the standard model of strong field ionization needs to be refined: the larger the atomic polarizability, the more important it becomes to account for the Stark shift of the energy levels and the deformation of the ion potential by the induced dipole.